Rain bag



FIG. 1 is a front perspective view of a rain bag showing my new design; and,

FIG. 2 is a perspective view thereof.

The broken line showing of a woman holding the bag and articles in the bag, in FIG. 2, is for illustrative purposes only and forms no part of the claimed design.

The rear and bottom are plain and not part of the claimed design. 

The ornamental design for a rain bag, as shown and described. 